cgitrc.5.txt: describe macro expansion of cgitrc options

This is a new feature in cgit-0.9 which was formerly undocumented.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 26 insertions, 4 deletions

diff --git a/cgitrc.5.txt b/cgitrc.5.txt
index 65b210f..10b86f3 100644
--- a/cgitrc.5.txt
+++ b/cgitrc.5.txt
@@ -39,13 +39,13 @@ agefile::
 	The first line in the file is used as input to the "parse_date"
 	function in libgit. Recommended timestamp-format is "yyyy-mm-dd
 	hh:mm:ss". Default value: "info/web/last-modified".
 
 cache-root::
 	Path used to store the cgit cache entries. Default value:
-	"/var/cache/cgit".
+	"/var/cache/cgit". See also: "MACRO EXPANSION".
 
 cache-dynamic-ttl::
 	Number which specifies the time-to-live, in minutes, for the cached
 	version of repository pages accessed without a fixed SHA1. Default
 	value: "5".
 
@@ -152,13 +152,13 @@ head-include::
 header::
 	The content of the file specified with this option will be included
 	verbatim at the top of all pages. Default value: none.
 
 include::
 	Name of a configfile to include before the rest of the current config-
-	file is parsed. Default value: none.
+	file is parsed. Default value: none. See also: "MACRO EXPANSION".
 
 index-header::
 	The content of the file specified with this option will be included
 	verbatim above the repository index. This setting is deprecated, and
 	will not be supported by cgit-1.0 (use root-readme instead). Default
 	value: none.
@@ -234,13 +234,14 @@ noheader::
 	Flag which, when set to "1", will make cgit omit the standard header
 	on all pages. Default value: none. See also: "embedded".
 
 project-list::
 	A list of subdirectories inside of scan-path, relative to it, that
 	should loaded as git repositories. This must be defined prior to
-	scan-path. Default value: none. See also: scan-path.
+	scan-path. Default value: none. See also: scan-path, "MACRO
+	EXPANSION".
 
 readme::
 	Text which will be used as default value for "repo.readme". Default
 	value: none.
 
 remove-suffix::
@@ -286,13 +287,14 @@ scan-path::
 	A path which will be scanned for repositories. If caching is enabled,
 	the result will be cached as a cgitrc include-file in the cache
 	directory. If project-list has been defined prior to scan-path,
 	scan-path loads only the directories listed in the file pointed to by
 	project-list. Be advised that only the global settings taken
 	before the scan-path directive will be applied to each repository.
-	Default value: none. See also: cache-scanrc-ttl, project-list.
+	Default value: none. See also: cache-scanrc-ttl, project-list,
+	"MACRO EXPANSION".
 
 section::
 	The name of the current repository section - all repositories defined
 	after this option will inherit the current section name. Default value:
 	none.
 
@@ -447,12 +449,32 @@ options are only acknowledged in repo-specific config files when
 "enable-filter-overrides" is set to "1".
 
 Note: the "repo." prefix is dropped from the option names in repo-specific
 config files, e.g. "repo.desc" becomes "desc".
 
 
+MACRO EXPANSION
+---------------
+The following cgitrc options supports a simple macro expansion feature,
+where tokens prefixed with "$" are replaced with the value of a similary
+named environment variable:
+
+- cache-root
+- include
+- project-list
+- scan-path
+
+Macro expansion will also happen on the content of $CGIT_CONFIG, if
+defined.
+
+One usage of this feature is virtual hosting, which in its simplest form
+can be accomplished by adding the following line to /etc/cgitrc:
+
+	include=/etc/cgitrc.d/$HTTP_HOST
+
+
 EXAMPLE CGITRC FILE
 -------------------
 
 ....
 # Enable caching of up to 1000 output entriess
 cache-size=1000